What is the battery life of the iPhone 4S in "real-world" tests? Is the battery designed to be replaced?

Officially, Apple estimates that the iPhone 4S provides 8 hours of talk time on 3G, 14 hours of talk time on 2G, 6 hours of web use over 3G, 9 hours of web use over Wi-Fi, 40 hours of music playback, 10 hours of video playback, and 200 hours of standby time.

Photo Credit: Apple, Inc. (iPhone 4S)

Those with sharp eyes or good memories will immediately note that these numbers are both better and worse than those Apple formally quotes for the earlier iPhone 4 (GSM) and iPhone 4 (CDMA) models:

	iPhone 4	iPhone 4S
Talk Time (3G):	7 Hours	8 Hours
Talk Time (2G):	14 Hours (GSM Only)	14 Hours
Battery Life (Web - 3G):	6 Hours	6 Hours
Battery Life (Web - Wi-Fi):	10 Hours	9 Hours
Battery Life (Music):	40 Hours	40 Hours
Battery Life (Video):	10 Hours	10 Hours
Standby Time:	300 Hours	200 Hours

Specifically, the iPhone 4S provides officially estimated longer talk time on 3G, but reduced web surfing over Wi-Fi and standby time.

Third-Party Battery Life Test Results

Although the official numbers may be a sufficient estimate for some, objective third-party tests provide a better estimate of battery life in the "real-world" under actual usage conditions. After all, most people tend to use their mobile devices for multiple tasks over the course of the day rather than for a single task non-stop.

Interestingly, of the dozen or so publications "blessed" to review the iPhone 4S prior to its official release, none covered its battery life.

However, two longer reviews from the always excellent iLounge and AnandTech -- both of which definitely are worth reading in their entirety -- did cover battery life in actual use.

After acknowledging that "Apple underpromised with the iPhone 4's battery estimates, [but] it comes closer to overpromising with the iPhone 4S," iLounge found:

While it's easy to claim that you'll probably still get around a day's worth of use out of a fully charged iPhone 4S if you were used to getting that sort of life out of the iPhone 4, the reality's not quite that simple. If you spend much of your day near a Wi-Fi network and only rely upon the iPhone 4S for web browsing and phone calling, you won't notice a major difference—unless you're thinking of switching to Sprint, in which case we'd be a little concerned. Similarly, if you use 3G data, plan to record or play videos, or want to listen to hours of audio during the day, you can expect greater battery drain from the iPhone 4S. Our advice for heavy iPhone users would be to keep a charger or spare battery pack handy during the day, as well as on trips.

After performing extensive testing of the iPhone 4S pitted against the iPhone 4 and other smartphones, AnandTech concluded:

I'd say Apple's claim of 8 hours of battery life is fairly realistic under some sort of continuous use/load. If you're constantly pulling data don't expect to see more than 5 hours, but if you're mostly reading/watching/consuming content you will get closer to 10 hours on the iPhone 4S. Call time falls at the longer end of the spectrum, but be warned: run a demanding 3D title and you'll see barely over 3 hours of use out of the iPhone 4S. It looks like any serious 3D gaming is going to have to be tethered or at least near a power outlet.

Battery Self-Replacement Possible

As the design of the iPhone 4S is quite similar to the iPhone 4, it shouldn't be a surprise that the battery likewise is relatively easy to replace although it still is not "swappable" or intended to be replaced by the end user.

AnandTech also discovered:

An extremely small jump in battery capacity, from 1420 mAh in the 4 to 1430 mAh in the 4S. This is a very small change that boosts the capacity in watt-hours from 5.25 to 5.3. In addition the 4S puts on a little bit of weight, from 137 to 140 grams, but again nothing major.

Apple offers to replace the iPhone 4S battery for US$79 plus US$6.95 for shipping in three to five business days. However, to access the battery in the iPhone 4S, it's simply a matter of unscrewing the two screws on the bottom of the device with a compatible screwdriver. This releases the back panel and the battery is readily accessible. It is not soldered either, so self-replacement for the technically skilled and steady of hand as well as professional third-party replacement both are quite possible.

Battery Life & Replacement Summary

Ultimately, the iPhone 4S provides respectable battery life that can provide "all day" use for many. Hardcore gamers, on the other hand, likely will want to pack an external battery pack. Although some may wish that the battery was "swappable" as well, at least it is fairly easy to replace, just like the iPhone 4.

In addition to Apple's official option, professional third-party services also are available to replace the battery in the iPhone models, often much more quickly and for less money, as well. Be sure to purchase your repair service or parts from a trusted company with extensive experience repairing iPhone devices.

Also see: How do I replace the battery in the iPhone 4S?